Method for measuring and calibrating centroid of coarse stage of photolithography tool

Abstract

A method for measuring and calibrating a centroid of a coarse stage of a photolithography tool by means of measuring an offset of the centroid relative to a midpoint of the coarse stage is disclosed. The method includes: individually performing closed-loop controls on parameters of the three degrees of freedom X, Y, and Rz of the coarse stage and converting the parameters into coordinates in a coordinate system of the coarse stage (); for each of the X and Y directions, estimating a range for the centroid (), equally dividing the range into N parts (), and designating each dividing point as an eccentricity (); obtaining N Rz direction positional deviations by conducting a compensation calibration and a calibration calculation based on each corresponding eccentricity (-); comparing a minimum of the N positional deviations with a preset Rz-direction positional deviation threshold (), completing the measurement if the latter is greater (), and otherwise designating a range between the eccentricities adjacently in front of and behind the eccentricity corresponding to the minimum positional deviation as a new range for the centroid (-) and repeating the measurement until the minimum is smaller than the preset threshold.